r5200 - /1.3/physical_constants.py -- March 23, 2008 - 16:34

Author: bugman
Date: Sun Mar 23 16:34:45 2008
New Revision: 5200

URL: http://svn.gna.org/viewcvs/relax?rev=5200&view=rev
Log:
Wrote the return_atomic_mass() function for returning the desired atomic mass.


Modified:
    1.3/physical_constants.py

Modified: 1.3/physical_constants.py
URL: 
http://svn.gna.org/viewcvs/relax/1.3/physical_constants.py?rev=5200&r1=5199&r2=5200&view=diff
==============================================================================
--- 1.3/physical_constants.py (original)
+++ 1.3/physical_constants.py Sun Mar 23 16:34:45 2008
@@ -108,3 +108,57 @@
 
 ArS = 32.065
 """Sulphur atomic mass."""
+
+
+# Function for returning the desired atomic mass.
+def return_atomic_mass(nucleus=None):
+    """Return the atomic mass for the given nucleus type.
+ 
+    @keyword nucleus:   The nucleus type.
+    @type nucleus:      str
+    @raises RelaxError: If the nucleus type is unknown.           
+    @returns:           The desired atomic mass.
+    @rtype:             float
+    """
+
+    # Protons, deuterons.
+    if nucleus == 'H':
+        return ArH
+    if nucleus == '1H':
+        return 1.0
+    if nucleus == '2H':
+        return 2.0
+
+    # Carbons.
+    if nucleus == 'C':
+        return ArC
+    if nucleus == '12C':
+        return 12.0
+    if nucleus == '13C':
+        return 13.0
+
+    # Nitrogens.
+    if nucleus == 'N':
+        return ArN
+    if nucleus == '14N':
+        return 14.0
+    if nucleus == '15N':
+        return 15.0
+
+    # Oxygens.
+    if nucleus == 'O':
+        return ArO
+    if nucleus == '16O':
+        return 16.0
+    if nucleus == '17O':
+        return 17.0
+
+    # Sulphurs.
+    if nucleus == 'S':
+        return ArS
+
+    # Unknown mass.
+    raise RelaxError, "The nucleus type " + `nucleus` + " is unknown."
+
+
+